The invention relates to a device for separating gases entrained with liquids being pumped. More specifically, the invention relates to a device for use in connection with well-head pumps for separating gases from the liquid being pumped. Still more particularly, the invention is concerned with a device for use in wellpoint dewatering systems.
Liquids pumped from below ground level generally contains an amount of air entrained with the liquid. Pumps designed to pump liquids from underground wells are hindered by the problem of separating gases present with the liquid to permit non-aerated liquid to reach the pump. Most well-head pumps are of the centrifugal type which can only reach maximum efficiency when gas free liquids are pumped since the denser liquid enables the pump to move a greater volume of fluid in a given period of time. In any pumping system, the capability of handling large volumes of gases is extremely desirable, for example, a ground dewatering wellpoint system often encounters a situation where the volume of water to be pumped is relatively small compared with the volume of gases extracted. In such systems, i.e., low water volume, it is desirable to connect a number of wellpoints by means of a manifold to a single well-head pump system. The limiting factor, however, is the volume of air that the pumping system can handle. Accordingly, the larger the number of wellpoints that can be handled by a single pump system, the more efficient and economical the operation.
Prior art liquid pumping systems have generally included some method and/or device for separating gases entrained in, and gases present with, the liquid being pumped. Heretofore, none of the known methods and devices have been completely successful in removal of the gases prior to the liquid entering the pump. One of the prior art techniques is shown, for example, in U.S. Pat. No. 2,318,251 to Moore, wherein a centrifugal pump is employed to drive water and a vacuum pump to effect discharge of air entrained in the water. A float member is disposed in a pipe which controls a valve. The valve, responsive to the rise of water in the pipe, controls introduction of air at atmospheric pressure into the pipe, thus reducing the vacuum provided by the vacuum pump.
Other techniques include such systems and devices as taught in U.S. Pat. No. 3,726,303 to Allen et al and U.S. Pat. No. 2,322,910 to Adney et al which disclose modifications of the system taught in Moore (supra) wherein a double valve structure carried by a water-operated float member and disposed within a water-containing chamber is used to seal the chamber from the intake of liquid and vent the vacuum source to air at atmospheric pressure when a rise in the water level causes the float member to rise.
A serious disadvantage of prior art gas and liquid handling valves and pumps resides in the fact that when the air handling pump uses oil to effect a seal, as is common in most vacuum pumps used today, droplets of water and moisture laden air from prior art wellpoint valves will tend to mix with the oil thereby creating sludge and contaminating the oil feed to the air handling pump. While the techniques, devices and systems heretofore proposed and used in the art have ameliorated the situation to some extent, none have provided a simple device which substantially completely separates all gases entrained in, and with, the liquid well ahead of where the gas enters the intake of the air handling and liquid pumps and includes means for automatically controlling the level of liquid within the device so as to prevent the liquid from entering the air handling pump.